Girl I’m interested in replies every few hours — should I pull back?

I’ve been talking to a girl on Instagram that I don’t know in real life. We’ve mostly been photo replying to each other and texting through the photo replies. I think she’s really attractive and I’m genuinely interested in her. She does respond, but it usually takes hours before she sees the photo and replies. I don’t double text, and I usually wait around 30 minutes before replying so I’m not coming off too eager. I’ve tried asking engaging questions and keeping things playful instead of dry. The thing is, the pattern doesn’t really change. She replies, but she doesn’t seem super invested and still takes a while each time.

For people who’ve experienced this — is this just normal when you don’t know someone personally yet? Or does slow replying usually mean low interest?